Warmer climate may repaint our beloved fall colors

KMSP - Colorful fall foliage can be seen in many parts of the United States, but the colors vary depending on the tree species that are dominant in any given region. In the eastern United States, the USDA Forest Service has identified ten forest types. Together, they paint a unique palette of vibrant fall colors. The map on the left in the image below shows the distribution of forest habitats across the eastern United States during 1990-1999.

Each forest type features a collection of tree species that are naturally confined to particular living conditions. Many factors determine where a certain tree species will grow like soil characteristics, elevation, land use, temperature, and precipitation.

The forever changing climate of the future will undoubtedly have an impact on what tree species can grow in different locations. To understand what may happen to the forests in the future, the Forest Service researchers created habitat maps in which they exchanged current climate data for climate conditions in the year 2100 that have been projected by computer models from NOAA’s Geophysical Fluid Dynamics Laboratory, the Hadley Centre, and the Department of Energy-sponsored Parallel Climate Model project.

The maps at center and right show where suitable tree habitats will be in the future under two different scenarios of greenhouse gas emissions, one with lower (but still increasing) emissions and one with higher. Which emissions scenario will most closely match future conditions is impossible to know because it depends on human and natural conditions alike, none of which can be forecasted with any certainty… especially with our constantly and quickly changing political landscape.

The projections show everything we would expect; a general northward shift in species because of the warming temperatures. Much of the Northeast loses its maple-beech-birch forests while the spruce-fir are gone altogether. A similar scenario takes place in Minnesota with all but the Arrowhead ending up with the typical yellow and brown makers of elm, ash, and cottonwood.

This is just one possible scenario of hundreds that could play out in our constant shifting climate… but I doubt you even thought about how those yellows, oranges, and reds you see each fall are so special and need to be cherished because who knows when they won’t be around anymore.

Remember that this is far from concrete information and that there are dozens of factors other than climate that determine where certain species of trees can grow, with animals and insects a large part of that equation, along with the shifting climate, and of course man. This is solely to get your noodle thinking about how truly fragile our environment is.